Master the built-in modules that come with every Python installation
No installation required. These modules are included with Python. Learn them once, use them everywhere.
Each guide teaches one library through hands-on examples, following the Build It methodology: one concept per page, checkpoints to verify understanding, and troubleshooting for common issues.
Random numbers, choices, shuffling, and sampling
Sleep, timestamps, and measuring duration
Dates, times, formatting, and timezones
Type hints and annotations
Read and write JSON data
File system and environment variables
Modern file path handling
Counter, defaultdict, deque, and more
Mathematical functions beyond basics